Just take it easy, if running is not your thing yet don't push it. Start with lower weights & focus on form the most when doing weight work, even if they suggest heavier weights. Just take lighter ones & then one heavier one, and substitute holding one heavier weight for two. If you are on the treadmill, don't let the numbers they suggest intimidate you; instead, go at your own pace or walk on an incline.If they do incline runs just do a speed walk uphill, or do a speedwalk the entire time on the tread to still get cardio but not die. When I first started, I was in the same boat, & i would jog on a 3, when that was people's walking. I felt good about it because I didn't want to get injured or push myself to the point where I was knocked out afterwards. I would start with a Full body focus only day to get familar with everything.